1. Field of the Invention
This invention relates to an improved lighting fixture reflector. More particularly, it relates to an improvement in lighting fixture reflectors which employ a sheet of metalized plastic as the reflecting element.
2. Background Art
Many types of lighting fixtures employ a reflector behind the light source to beam the light in a desired direction. One approach to forming these reflectors is to employ a sheet of metal which has been highly polished. Another approach is to use a sheet of metal which has been plated. A third approach is exemplified in U.S. Pat. No. 4,307,150 of Roche, which discloses using as a reflector a polymeric sheet upon which has been deposited a layer of evaporated metal. This polymeric sheet is then bonded to a suitable rigid support. Another reference which relates to this type of polymer sheet-based reflector is U.S. Pat. No. 4,666,263 of Petcavich, which describes a particular type of metalized coating made up of silver and a stainless steel or other corrosion-resistant metal protecting layer. For the past several years, Southwall Technologies Inc., of Palo Alto, Calif., and Deposition Technology, Inc., of San Diego, Calif., have marketed metalized plastic sheet materials for use in reflectors. These materials have been based on a poly(ethylene terephthalate) film with silver as the metal layer. These materials can also include an adhesive layer on the silver for gluing the film to the rigid support. In the Southwall product in the past, the plastic film employed has been conventional poly(ethylene terephthalate), such as du Pont's MYLAR. While this material has been very advantageous in offering a smooth surface, a high degree of transparency and resistance to many environmental agents, such as water and/or oxygen, the overall life of the metalized films has been less than optimal because of delamination of the silver from the polymer or discoloration of the silver film over extended periods of time.
Since the delamination and the discoloration directly reduce the efficiency of the reflector, they are serious problems. Any improvement which could be made so as to extend the useful life of the film and the reflectors made from it would be valuable.